Only once. When I was a sophomore In high school I was up very late playing Pokemon in my bed, probably until some time close to 3 am. I closed my DS and had begun to try to sleep when an incredibly bright yellow light started to leak through my blinds and flood the room. I was slightly irritated, assuming my asshole neighbors were shining a spotlight into my room or something. However, when I open my blinds I saw something amazing. Hovering roughly fifteen feet in the air was an enormous three dimensional diamond shaped object, shaped sort of like two triangular prisms connected at their bases. The light radiating from it was such that it looked like the light source was either behind the object, also floating, or was emanating from the ridges and corners of the object. My stomach fell down around my ankles and as I watched this object floated incredibly slowly up and out of the yard at an angle. Never got an explanation not have I heard of a similar sighting. This was in Houston Texas roughly three years ago.